10GBASE-T training algorithm

ABSTRACT

A method of identifying and correcting each of the changes that may occur with wire pairs between the transmitter and receiver in Ethernet 10 GBase-T cabling is provided. The method includes four wire pairs A, B, C and D, a polarity swapping and scrambler state machine that determine if the chosen pair matches the requirements for pair A. A slave Tap state machine generates a rule for correct B, C and D patterns based on a pair chosen as pair A. The cables B, C and D are iteratively swapped to rearrange the pair mapping into the polarity swap state machine, and a deskew state machine identifies the latency difference between the different pairs. If the rules are not satisfied, a new pair A is designated at the swapping state machine and the process is repeated until the rules are satisfied.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.12/012,725, filed Feb. 1, 2008. application Ser. No. 12/012,725 claimsthe benefit of U.S. Provisional Patent Application 60/900,180 filed Feb.7, 2007, which is hereby incorporated by reference.

FIELD OF THE INVENTION

The invention relates generally to electronic communication systems.More particularly, the invention relates to a training pattern to enablerecognition of proper wire-pair orientation and correction in electroniccommunication systems.

BACKGROUND

In Ethernet 10 GBase-T cabling, the data is sent over four pairs ofwires. Between the transmitter and receiver, the pairs can be swappedwith each other, and the wires in a pair can be swapped. Thesereconfigurations can result in an inverted signal or the latency of thefour pairs can differ. 10 GBASE-T, or IEEE 802.3an-2006, is a standardto provide 10 gigabit/second connections over conventional unshielded orshielded twisted pair cables, over distances up to 100 m. This standardmandates specific training patterns to enable recognition of the propercorrection, but does not provide a means to find the proper correctionsfrom all the possibilities. Accordingly, there is a need to develop analgorithm to efficiently search the possible corrections and identifythe correct one.

SUMMARY OF THE INVENTION

The current invention is a method of recognizing inverted signals andlatency difference in wire pairs between a transmitter and receiver in10 GBase-T Ethernet cabling due to wire pair mismatch, and correctingthe inversion and latency by swapping the cable orders. The methodincludes providing four pairs of wires, wherein the wires transmit databetween the transmitter and the receiver. The wire pairs include pairsA, B, C, and D, whereas the pairs are arranged in a quadrille patternhaving two top pairs and two bottom pairs. The method includes providinga pair swapping state machine, where the swapping state machine selectsone pair from the top pairs, whereas the selected pair is designated aspair A. A polarity swapping and scrambler lock state machine isprovided, where the lock state machine determines if the designated pairA is a correct choice for position A. The lock state machine thendetermines if the selected pair is inverted. If the selection for A isnot correct a next pair of the wires is designated as pair A and thedetermination is repeated until the requirements for pair A are met andthe pair is not inverted. A slave tap state machine is provided, wherethe tap state machine establishes a rule for a correct B, C, and Dpattern based on the determined pair A. The lock state machine is usedto designate a second top pair as pair B. The lock state machine isfurther used to designate a first bottom pair as pair C and to designatea first bottom pair as pair D. A deskew state machine is provided, wherethe deskew state machine compares all the designations over all possiblelatencies with the rules generated by the slave tap machine, where ifthe rules are not satisfied, the cable swap state machine reverses thedesignated pair C with designated pair D. The deskew state machine isused to re-compare all the designations over all possible latencies withthe rules generated by the slave tap machine, where if the rules are notsatisfied, a new pair A is designated at the swapping state machine andthe process is repeated until the rules are satisfied.

DETAILED DESCRIPTION OF THE INVENTION

Details of various embodiments of the present invention are disclosed inthe following appendices:

Appendix A. Appendix B. Appendix C.

As one of ordinary skill in the art will appreciate, various changes,substitutions, and alterations could be made or otherwise implementedwithout departing from the principles of the present invention.Accordingly, the examples and drawings disclosed herein including theappendix are for purposes of illustrating the preferred embodiments ofthe present invention and are not to be construed as limiting theinvention.

1. A method of recognizing and correcting wire pair swapping between atransmitter and receiver in 10 GBase-T Ethernet cabling comprising: a.providing four pairs of wires, wherein said wires transmit data betweensaid transmitter and said receiver, whereby said wire pairs comprise A,B, C, and D, whereas said pairs are arranged in a quadrille patterncomprising two top pairs and two bottom pairs; b. providing a cableswapping state machine, wherein said swapping state machine selects onepair from said top pairs, whereas said selected pair is designated aspair A; c. providing a polarity swapping and scrambler lock statemachine, whereby said lock state machine determines if said designatedpair A is a correct choice for position A, whereas said lock statemachine determines if said selected pair is inverted, wherein if saidselection for A is not correct a next pair of said wires is designatedand said determination is repeated until said requirements for pair Aare met and said pair is not inverted; d. providing a slave tap statemachine, wherein said tap state machine establishes a rule for a correctB, C, and D pattern based on said determined pair A; e. using said lockstate machine to designate a second said top pair as pair B; f. usingsaid lock state machine to designate a first said bottom pair as pair C;g. using said lock state machine to designate a first said bottom pairas pair D; h. providing a deskew state machine, wherein said deskewstate machine compares all said designations over all possible latencieswith said rules generated by said slave tap machine, whereby if saidrules are not satisfied said cable swap state machine reverses saiddesignated pair C with designated pair D; i. using said deskew statemachine to re-compare all said designations over all possible latencieswith said rules generated by said slave tap machine, wherein if saidrules are not satisfied a new pair A is selected and steps b through iare repeated until said rules are satisfied.